Currently there are two types of blow out preventers, a shear blind (cut and seal) and casing shear rams (cut only). Both employ gate valve technology to shear the pipe and close the well. The shear rams are protruded into the well bore from each side, shearing the drill pipe with a scissor style action. To provide the needed forces, large actuators are mounted perpendicularly to the axis of the well bore.
In such systems, the blades have to be kept close together for operability, so that they slide over each other. The forces required to accomplish this when heavy metal objects are being sheared are difficult to achieve. At present, achievable force appears to be less than 1,000,000 lbs.
It has been found that the above configuration and available force are not enough to cut all the configurations of pipe, tube or tools that may be used in the drilling process. What is needed is a configuration that allows enough force to be applied to the cutting mechanism to cut the various configurations of tubular components that may be present. It is an object of this invention to supply such a configuration.
It is a further object of this invention to provide a blow out preventer apparatus which is simpler and more reliable than the configurations which employ actuators perpendicular to the wellbore.
It is another object of this invention to provide a blow out preventer which is capable of providing higher forces than blow out preventers in current use.